Principal goals for cartons or containers used in the fast food industry wherein only a single use is contemplated include the formation of cartons to both properly accommodate the foodstuffs, and to in themselves be an economical and practical product.
As such, the carton, when open, must be able to allow for quick and easy introduction of the food product. The carton must also be able to both close and lock in a positive manner, and easily open for access to the carton contents Another desirable feature, particularly in preassembled fast food cartons folded from blanks of paperboard or the like, is the capability for a compact nesting of the cartons for storage and shipment. As an example of cartons incorporating the above features, attention is directed to applicant's prior U.S. Pat. No. 4,877,178, issued Oct. 31, 1989.
Two part cartons, for example the hinged carton of the above patent, normally provide for an interlock between the tray and overlying cover by utilizing complementary although different interlocking means, usually projections or tabs on one component and tab receiving recesses, slits or notches on the companion component.
The provision of two distinct locking elements on the tray and cover of a carton, wherein selected ones of the locking elements include internal cuts or openings in a blank as opposed to locking tabs or the like defined along the edge of the blank, require a rather elaborate die construction to form and properly position the internal cuts.
The conventional use of internal slits, notches or openings as an element of the locking means between the tray and cover also gives rise to other potential problems. Such openings, not only weaken the material and affect the structural stability of the formed carton, providing potential tear areas, but also tend to interrupt areas on which printed copy or indicia appears. Further, the actual formation of such openings and the removal of the cut material from the interior of the blank either at the time of forming or as the carton is put into use, introduce additional manufacturing complexities.
While cartons for fast food and the like are provided in a variety of sizes to generally correspond with the foodstuffs to be received therein, such cartons are conventionally of rectangular configuration and without regard to the specific shape of the goods to be received. For example, notwithstanding that the conventional pizza is circular, the conventional pizza box is square. In such situations, there is wasted space within the carton and the use of excess paperboard or the like in the formation of the "oversized" carton.